Showing papers on "Solar cell published in 1978"

Amorphous semiconductors equivalent to crystalline semiconductors produced by a glow discharge process

Abstract: A method of making an amorphous semiconductor film or the like having desirable photoconductive and/or other properties comprises depositing on a substrate a solid amorphous semiconductor film including at least one element, by glow discharge decomposition of a compound containing said at least one element and at least one alterant element in an atmosphere separately containing at least one different alterant element, wherein the plurality of different alterant elements comprise at least fluorine and are incorporated in said amorphous semiconductor film during the deposition thereof yielding an altered amorphous semiconductor material having reduced density of localized states in the energy gap thereof so that greatly increased diffusion lengths for solar cell application are obtained and modifiers or dopants can be effectively added to produce p-type or n-type amorphous semiconductor films so that the films function like similar crystalline semiconductors.

The operation of the semiconductor‐insulator‐semiconductor (SIS) solar cell: Theory

Abstract: Recently 12% efficient indium tin oxide (ITO) on silicon solar cells have been reported. Experiments indicate the presence of a thin interfacial insulating layer. Thus, these devices appear to belong to a class of semiconductor‐insulator‐semiconductor (SIS) solar cells where one of the semiconductors is a degenerate wide‐band‐gap oxide. We have developed a theory in terms of minority‐carrier tunnel current transport through the interfacial layer where one semiconductor is in a nonequilibrium mode. The wide‐band‐gap semiconductor serves to block band‐to‐band majority‐carrier current and thus, in principle, give better device performance than with an MIS solar cell. The effects of interfacial layer thickness, substrate doping level, surface states and interface charge, temperature on the performance of SIS solar cells have been calculated. These indicate that real‐world ITO on silicon cells should be able to achieve 20% efficiency under AMl illumination. Other combinations of semiconductors would yield even...

Self-reconfiguring solar cell system

Abstract: A self-reconfiguring solar cell array wherein some of the cells are switched so that they can be either in series or in shunt within the array. This feature of series or parallel switching of cells allows the array to match the load to achieve maximum power transfer. Automatic control is used to determine the conditions for maximum power operation and to switch the array into the appropriate configuration necessary to transfer maximum power to the load.

Enhanced photoelectrochemical solar‐energy conversion by gallium arsenide surface modification

Abstract: In the n‐GaAs/Se=–Se=x–OH−/C liquid junction solar cell, modification of the semiconductor surface by incorporation of ruthenium increases both the fill factor and the open‐circuit voltage and improves the reproducibility of performance. The power conversion efficiency of the modified cell is 12% under ∼100 mW/cm2 sunlight. Surface metal atoms or ions are shown to alter GaAs cell behavior widely; Ru represents a case for which the effect on cell performance is both positive and persisting.

Solar Energy Conversion: The Solar Cell

Abstract: Part 1 Energy needs - energy sources: consumption conventional sources of energy alternative energy sources nuclear fusion solar energy temperature differences thermodynamics ocean temperature-difference generators solar-thermal solar-electric references. Part 2 The sun and sunlight: sunlight geometrical effects weather light collection lens systems mirrors optical materials maximum optical concentration references. Part 3 Semiconductors: crystal structure quantum mechanics and energy bands electrons and holes currents recombination and carrier lifetime junctions references. Part 4 Light-semiconductor interaction: reflection light interaction preliminary material selection absorption reflection and absorption references. Part 5 Basic theoretical performance: local electric fields PN junction electrical characteristics heterojunction electrical characteristics electrical characteristics of schottky junctions open circuit voltage and short circuit current optimum power conditions references. Part 6 Solar cell configuration and performance: optical orientation device design - minority carrier collection device design - saturation current device design - series resistance solar cell performance - discussion references. Part 7 Advanced approaches: temperature effects heat flow within a solar cell optical concentration - photocurrent performance under concentration references. Part 8 Advanced approaches - II: second stage solar power systems third generation solar cell systems miscellaneous approaches references. Part 9 Polycrystalline and amorphous solar cells: polycrystalline solar cells cadmium sulfide/copper sulfide copper indium selenide (CIS) polycrystalline silicon thin film cadmium telluride other possibilities for polycrystalline solar cells final comments on polycrystalline solar cells amorphous material based solar cells amorphous silicon concluding remarks references. Part 10 Concluding thoughts: economics electrical energy storage the system final words references.

Solar cell materials and their basic parameters

Abstract: Parameters such as the energy gapE g , open circuit voltageV oc , short circuit current densityj sc , fill factor F.F., efficiency η, antireflection coating condition A.R. and illumination conditions of currently known photovoltaic diodes are reviewed and tabulated, followed by some critical comments.

Method and apparatus for solar power lighting

Abstract: Solar powered and/or augmented lighting systems embodied within conventional hollow light pole configuration incorporating a solar power lamp cell. A plurality of solar cells are disposed in an array about an upstanding light pole of conventional design of the type having a hollow interior and laterally extending lighting elements. The lighting element itself is provided in a configuration incorporating a solar cell atop a storage battery atop a light source, such as a bulb, operable from said light power system. The lighting cell is selectively powered by either a storage battery system operable in conjunction with the solar panel array and/or the solar power network incorporated therein. A network of electrical storage cells are disposed within the hollow configuration of the light pole and supported upon an elevator system for facilitating access thereto. In this manner, the overall consumption of energy from conventional power lines may be reduced and/or eliminated. The commercial lines may remain connected to said light poles for augmented power during periods of low solar energization and for purposes of original solar collector orientation.

Planar solar energy converter and concentrator based on uranyl-doped glass

Abstract: A MAJOR improvement of solar cell efficiency is described here which uses a fluorescent plane glass to convert and concentrate the ultraviolet (UV) and blue part of the solar spectrum, thus increasing the possibilities of photovoltaic solar energy conversion. An advantage of our device is that the heat energy coming directly from the Sun will be dissipated over the large area of the glass and only the energy in the visible part of the spectrum will reach the solar cell. Moreover, the excess between the absorbed and band-gap energy which is evolved as heat in the solar cell will be diminished by decreasing the difference in wavelength between the useful and excess energy, and thus the solar cell will be heated to a much lesser extent.

Concentrator solar cell array module

Abstract: A concentrator solar cell array module having a metallic heat sink with a planar mounting surface. A semiconductor spacer is provided. The semiconductor spacer is provided with a layer of insulating material in the form of silicon oxide. The silicon oxide surface is secured to the mounting surface of the heat sink by a thermally conductive adhesive. A semiconductor solar cell is provided. Solder is utilized for securing the solar cell to the spacer. A glass cover is secured to the solar cell by an adhesive. The glass cover is provided with a textured surface to cause diffusion of the light impinging upon the solar cell.

Method of manufacturing solar cells, utilizing single-crystal whisker growth

Abstract: A solar cell with semiconductor body consisting of single crystal semiconductor whiskers which are grown on a substrate surface permitting relatively inexpensive manufacture and high efficiency of the solar cell is disclosed.

Method of removing the effects of electrical shorts and shunts created during the fabrication process of a solar cell

Abstract: A method of removing the effects of electrical shorts and shunts created during the fabrication process and improving the performance of a solar cell with a thick film cermet electrode opposite to the incident surface by applying a reverse bias voltage of sufficient magnitude to burn out the electrical shorts and shunts but less than the break down voltage of the solar cell.

Photoacoustic determination of photovoltaic energy conversion efficiency

Abstract: Photoacoustic (i.e., photocalorimetric) measurements on photovoltaic devices can directly yield their energy conversion efficiency. This is illustrated for a Si solar cell, for which case excellent agreement is found with normal electrical measurements. In addition, the photoacoustic spectra under load and at open‐circuit conditions are reported and compared with the cell’s spectral response. Together, such measurements can provide information on the wavelength dependence of the cell performance as well.

Amorphous silicon MIS solar cells

Abstract: AMORPHOUS silicon grown by the rf glow discharge decomposition of silane in the process developed by Spear and Le Comber1,2 is one of the most promising materials found so far in the search for a cheap, large-area solar cell. Only two results, albeit encouraging, have been reported by RCA for p–n cells3 (AMI efficiency 2.4%) and anti-reflection coated platinum Schottky barrier cells4 (AMI efficiency 5.5%), but with area only ≤2×10−2 cm2. We report here the achievement of comparable efficiencies for a Schottky barrier cell, incorporating an insulating layer between the metal and semiconductor (an M–I–S cell) and with significantly greater area. The insulating layer is tailored to compensate for the low work function of the cheaper barrier metal (nickel) which we have used5–9, leading to higher cell voltages otherwise obtainable only with higher work function metals. This is a significant step forward in the development of large area terrestrial solar cells.

Schottky barrier amorphous silicon solar cell with thin doped region adjacent metal Schottky barrier

Abstract: A Schottky barrier amorphous silicon solar cell incorporating a thin highly doped p-type region of hydrogenated amorphous silicon disposed between a Schottky barrier high work function metal and the intrinsic region of hydrogenated amorphous silicon wherein said high work function metal and said thin highly doped p-type region forms a surface barrier junction with the intrinsic amorphous silicon layer. The thickness and concentration of p-type dopants in said p-type region are selected so that said p-type region is fully ionized by the Schottky barrier high work function metal. The thin highly doped p-type region has been found to increase the open circuit voltage and current of the photovoltaic device.

Solar cell module

Abstract: An improved solar cell module for use in terrestrial environments, characterized by an internally reflective plate having a planar surface of incidence and an opposed textured surface, a plurality of uniformly spaced silicon solar cells having the active surfaces thereof bonded to portions of the textured surface, and a layer of diffusely reflective matter applied to the textured surface in surrounding relation with the solar cells for reflecting solar energy to strike the surface of incidence at such angles as to be internally re-reflected and caused to progress toward the active surfaces of the solar cells, whereby concentration of incident flux on the solar cell is achieved without increased module depth.

Analysis of the interaction of an electron beam with a solar cell—II

Abstract: The short-circuit current generated by the electron beam of a scanning electron microscope when it impinges on the N-P junction of a solar cell is known to be dependent on the configuration used to investigate the cell's response, and the situation for one specific configuration is analyzed. This configuration is the case in which the highly collimated electron beam strikes the edge of a planar junction a variable distance away from the edge of the depletion layer. An earlier treatment is generalized to encompass the ohmic contact at the back surface. The analysis employing Fourier and Wiener-Hopf techniques shows that it is impractical to determine the bulk diffusion length of a solar cell by a SEM used in the studied configuration unless the ohmic contact is partially removed.

A 15% efficient silicon MIS solar cell

Abstract: Substantial improvements in energy conversion efficiency are reported for silicon MIS solar cells fabricated on both single‐crystalline and semicrystalline substrates. Based on active area, AM1 efficiencies of 15.1% and 12.6%, respectively, have been obtained for 3.1‐cm2 cells at 26 °C.

The influence of interface state and energy barriers on the efficiency of heterojunction solar cells

Abstract: A heterojunction solar cell, in which interface recombination and arbitrary energy barriers at the interface occur, is analysed to find the optimum structure. Thermionic emission theory is used; it is assumed that one type of carriers are majority carriers at the interface and that their concentration can be known a priori. It is shown that these assumptions do not seriously limit the applicability of the theory. The results are discussed in the case when one semiconductor is much more heavily doped than the other, which is a condition that certainly improves the efficiency of the solar cell.

Method of fabricating solar cell modules

Abstract: The solar cell module of this invention is fabricated by placing an array of solar cells in a suitable mold having a bottom surface, an entry port and an exit port. A light transparent superstrate effectively serves as the top for the mold and is placed over the array of solar cells in the mold. The superstrate is spaced from the array such that the superstrate does not come in contact with the top surface of any of the cells or interconnectors of the solar cell array. Clamp means are provided to hold the superstrate in position while encapsulant is pumped into the mold under pressure through the inlet port in an amount sufficient to fill the mold. Thereafter the assembly can be placed in an oven and heated for a time sufficient to cure the encapsulant and bond the materials to each other.

Inverted amorphous silicon solar cell utilizing cermet layers

Abstract: An amorphous silicon solar cell incorporating a transparent high work function metal cermet incident to solar radiation and a thick film cermet contacting the amorphous silicon opposite to said incident surface.

Method for forming p-n junctions and solar-cells by laser-beam processing

Abstract: This invention is an improved method for preparing p-n junction devices, such as diodes and solar cells High-quality junctions are prepared by effecting laser-diffusion of a selected dopant into silicon by means of laser pulses having a wavelength of from about 03 to 11 μm, an energy area density of from about 10 to 20 J/cm 2 , and a duration of from about 20 to 60 nanoseconds Initially, the dopant is deposited on the silicon as a superficial layer, preferably one having a thickness in the range of from about 50 to 100 A Depending on the application, the values for the above-mentioned pulse parameters are selected to produce melting of the silicon to depths in the range from about 1000 A to 1 μm The invention has been used to produce solar cells having a one-sun conversion efficiency of 106%, these cells having no antireflective coating or back-surface fields

Optical seed sensor for a seed planter monitor

Abstract: An optical seed sensor for a seed planter monitor utilizes light emitting diodes and a rapidly-responding light-receiving solar cell mounted in a seed dispensing chute A solar cell light shield with a slit narrower than the diameter of a typical seed is mounted adjacent to the solar cell When a seed passes the light shield, the voltage output of the light-receiving solar cell is temporarily reduced in response to a change in intensity of light at the solar cell Electronic circuitry converts such solar cell voltage fluctuations into electrical counting pulses for the seed planter monitor The rapidly-responding solar cell, the partially shielded solar cell and the electronic circuitry cooperate to discriminate between closely spaced or partially overlapping seeds passing through the dispensing chute in order to achieve accurate seed counting

A possible explanation for the photovoltaic effect in indium tin oxide on InP solar cells

Abstract: Recently, Sree Harsha and co‐workers reported a 14.4% efficient n‐indium tin oxide/p‐InP solar cell. In principle, it is difficult to visualize a high‐efficiency photovoltaic device with this particular structure because of large interfacial defects due to crystal structure and lattice mismatch. However, we propose an explanation for the operation of this solar cell based on the presence of a thin interfacial insulating layer between the indium tin oxide and the InP. The operation is similar to tunnel MIS solar cells where the metal is replaced by a degenerate wide‐band‐gap oxide (indium tin oxide) semiconductor. Our calculations show that such semiconductor‐insulator‐semiconductor solar cells can yield efficiencies as high as 26% (AM2) with InP as the base semiconductor.

Universal solar cell/conductor junction element and solar panel embodying same

Abstract: A solar electric power generating panel (solar panel) includes one or more universal electrical junction elements of approximately the same size and shape as conventional solar cells mounted along with the cells on a solar array substrate at any selected cell position or positions of the cell array. Each junction element has terminals which may be electrically connected to interconnects of the solar cells and electrical conductors such as lead wires of the cell array in such a way as to condition the element to serve as a series string termination with or without blocking diodes, an electrical voltage tap with or without blocking diodes, or a mounting for cell shunting diodes. Automatic assembly tooling may be utilized to assemble and electrically connect the solar cells, conductors, and junction elements into a completed solar array.

Electrochemical solar cell based on a sprayed CdS film photoanode

Abstract: Electrochemical studies of the CdS film deposited onto a transparent conductive SnO2-coated glass slide by chemical spray deposition were performed in aqueous polysulphide solutions and the output characteristics of the electrochemical photocell (sprayed CdS film/polysulphide electrolyte/Pt) were measured. It was proved to be possible to construct a regenerative photocell free from the light losses through the polysulphide solution path by illuminating the CdS film anode through the SnO2-coated glass. Quantum yield and the maximum energy conversion efficiency of this photocell for monochromatic excitation of 480 nm were about 8% and 0.5%, respectively. It is concluded that the poorer quantum yield of this photocell employing CdS film than that of a photocell employing single crystal CdS can be attributed to the existence of lattice imperfections in the film.

Cermet layer for amorphous silicon solar cells

Abstract: A transparent high work function metal cermet forms a Schottky barrier in a Schottky barrier amorphous silicon solar cell and adheres well to the P+ layer in a PIN amorphous silicon solar cell.

Novel materials and devices for sunlight concentrating systems

Abstract: Photovoltaic conversion under concentrated sunlight is a highly promising technique that could make solar-electric power generation economically competitive with fossil fuel power generation by the mid-1980s. An economic analysis has been performed which demonstrates that solar cell efficiency, concentrator efficiency, and concentrator cost are the most important parameters in a concentrating photovoltaic system; solar cell cost is only of secondary importance (at least for Si solar cells). Six novel structures are described, including modified conventional Si cells, Ga1-xAlxAs/GaAs devices, interdigitated cells, vertical and horizontal multijunction cells and "multicolor" devices.

Integrated solar cell array

Abstract: An integrated, monolithic array of solar cells wherein isolation between cells permits series interconnection of the cells to provide an output voltage for the array equal to the sum of the voltages of the unit cells. Although normal PN junction isolation is ineffective when exposed to light, the present structure includes a form of junction isolation that is effective when exposed to light, or to other radiation. For example, a band of heavily doped P-type silicon, formed by thermomigration of aluminum through an N-type wafer, provides such isolation.